Subcutaneous Schwannoma on the leg with hemorrhagic cystic degeneration: a case report

We report a case of a 64-year-old woman who had a subcutaneous schwannoma accompanied by hemorrhagic cystic degeneration in the left lower extremity. The patient presented with a progressively enlarging subcutaneous mass over an 8-year course, accompanied by activity-induced dull pain. Physical examination revealed a firm, well-defined nodule measuring 5.0 × 3.5 × 0.5 cm, with a negative Tinel's sign. Ultrasonography initially led to misdiagnosis of the lesion as a hemangioma; histopathological examination following complete surgical excision confirmed schwannoma. Microscopic analysis demonstrated characteristic Antoni A areas (featuring palisading spindle cells and Verocay bodies) and Antoni B (showing myxoid degeneration, cystic changes, and hyalinized vasculature). Subcutaneous schwannomas are prone to misdiagnosis because of the absence of typical imaging features. This imaging limitation necessitates a multidimensional analysis that integrates imaging with clinical manifestationsand histopathological features for accurate identification and differential diagnosis. Complete surgical excision achieved local disease control, and no recurrence was observed during the 4-year follow-up.This case highlights the importance of considering schwannoma in the differential diagnosis of chronic subcutaneous lower extremity masses. Establishing a "clinical-imaging-pathology" tripartite diagnostic framework is critical for early and precise management.Although photodynamic therapy or photodiagnosis was not performed in the present case, accurate recognition of rare superficial tumors with atypical manifestations may support appropriate lesion characterization before selecting diagnostic or therapeutic strategies, including photo-based approaches when clinically applicable.